Film gate



3 T. c. MCCULLOCH ET AL 1,873,443

FILM GATE Filed March 5, 1930 INVENTOR Theodore G M2 Cal/och l ATTORN EY Patented Aug. Z3, 193Z UNITED STATES PATENT OFFICE THEODORE C. MCCULLOCH, NEW YOBK N.

FOREST HILLS, PENNSXLVANIA, ASSIG NORS TO WESTINGHOUSE ELECTRIC & IAN- I UFACTUBING COMPANY, A CORPORATION OF PENNSYLVANIA,

Y., AND THADDEUS R. GOLDS'IBOROUGH, OF

FILM earn Application filed March 8,

Our invention relates to improvements in cinematographic apparatus and it has partlcular relation to the film-tensiomngmeansused therein.

The tensioning device is usually called a film-gate and consists of an aperture plate and a shoe-carrying plate movable relative in this position, since an aperture plate or a shoe plate, having a tendency tomove during the insertion or the removal of the film, may

hamperthe operator in his work and thus ma cause considerable damage to the film.

inally, as the film should present a smooth surface to the projection lens and, moreover, as this surface should be at a fixed distance position, must be held rigidly in this position and its parts must not move relative to each other because of'the vibration of the machine. A rapid periodic motion of the gate parts results in a periodic fading of the picture on the screen, a phenomenon that is notonly disagreeable to the observer but iillso has a'harmful physiological effect upon Film-tensioning means made according to the teachings of the prior art,'of which we are, aware, may be divided into several classes, with regard to their moving and locking contrivances.

1. Gates equipped with spring-actuated means for clamping the film but lacking any mechanical means for locking their movable parts either open or in closed position.

2. .Gates equipped with spring-actuated means forclamping the film, and latch or trigger means for locking their movable parts in open position but lacking means for 1930. Serial Np. 483,297.

locking their movable parts in closed position. 1

3. Gates equipped with toggle or latch means for locking their movable parts both in open and in closed position. I To manipulate successfully the gates of class 1, extraordinary agility is required. Furthermore, the shoe plates of the gates of class 1 and class 2 have a tendency to vibratewith the machine when in closed posi- 00 tion. Again, the latch or trigger arrangements of class 2 and the toggle arrangements of class 3 have a tendency to wear rapidly and thus occasion considerable trouble to those manipulating the apparatus. Finally, 65 the toggle locking means is ordinarily comlicated in its structure and, hence, a failing 1n one'of its parts may occasion difliculties with the pictures on the screen not easily traceable to the particular part. fusion resulting from such situation is invariably as costly as it is aggravating. ,It is, accordingly, an object of our invention to provide a film gate that can be openedwith facility and that can be locked rigidly .in its open and in its closed position. relative to the lens, the gate, when in closed I -of a'film-tensioning-devlce relative to the other, the shaft of one of these plate-moving means being slidably mounted in its bearing, and the supporting bracket of the plate ear-' rying its coacting member being e nippedwith indentations for holding the en of the slidable shaft of the former at oints corresponding to the extreme relative positions of the movable plates of the gate.

I The novel features that we consider charac-- Y I teristic of our invention are set forth with The con- 70 i i read in connection with the accompanying drawing in which;

Fi 1 is a view,'in front elevation, of a specific form of our improved film gate.

Fi 2 is a sectional view, taken on the line II- I of Fig. 1, and showm in addition a 2 number of appurtenances o a motion pic- .ture machine in their proper relationship to the film gate.

Fig. 3 is a view, in perspective, of the gatemoving shaft and its parts.

Fig. 4 is-a view, in front elevation, of an aperture mask the purpose of which will be described hereinafter.

Fig. 5 is a view, in side elevation, of the aperture mask. a

Fig. 6 is a view, in front elevation, of an aperture-mask-locking plate.

Fig. 7 is a view, in side elevation, of the aperture-mask-locking plate.

Fig. 8 is a view, in end elevation, of a part of the machine that will be discussed hereinafter.

Fig. 9 is a view, in rear elevation, of the unit comprising the aperture plate and the supporting plate.

The apparatus shown in the drawing comprises a plate 1 adapted to support the gate, equipped at its corners with a plurality of clearance holes 2 for screws that fasten it to the main plate of the machine and having located, between its horizontal center line form substantially a T section therewith. A

horizontal groove 8 is cut in the aperture plate 6 in such manner as to completely enclose the aperture, anda plurality of metallic strips 9, adapted to support the margins of the film 10, brid e the groove and are fastened rigidly to t e aperture-plate by a plurality of screws 11.

It has been the custom, in the cinematographic art, to provide an aperture mask to give the picture on the screen a rectilinear margin. and thus to lend it a neat appearance.

Furthermore, in acoustic-cinematography, a modified form of mask is necessary in order to cover the sound track that would otherwise appear at one margin of the picture, thus presenting a configuration highly distracting to the observer.

By reason of the above requirements, an

aperture-mask 12, an embodiment of which is shown in Figs. 4 and 5, is adapted to be slidably mounted in the slot formed between the groove 8 in the aperture piate 6 and the strips 9 bridgin the groove. e aperture mask 13 held rigi ly in position, when the locking plate 13 is inserted behind it, causing the edges of a raised section 14, which encloses the aperture, to be locked between the edges of the strips.

A plurality of vertical slots '15, located symmetrically near the upper end of the aperture plate, permits the passage of the flan es 16 of a guiding idler, that are rotata (11y mounted on a shaft 17 supported at its en s by pivots 18 mounted in bearings 19 cast integral with the plate 6.

A plurality of vertical brackets 20, also cast integral with the aperture late 6, are,

adjacent to the vertical sides of t e aperture 7. The brackets 20 are equipped with vertical tracks 21 to guide the dowser 5, to which reference was made above and, cast integral with them at their upper ends, are a plurality of bearings 22 to support, in a manner permitting longitudinal displacement and rotation about its axis, a shaft 23 that actuates the movable parts of the gate and will now be described in detail. I

A knurled knob 24 having a collar 25 integral wit-h it, is rigidly pinned to the shaft 23 at one end, and a pinion 26, also having a collar 27 integral with it, is rigidly pinned near the other end. The pinion 26 meshes with a rack 28 and thus moves, in a horizontal direction, a plate 29 in which the rack 28 is mounted when the knob 24 is turned.

At the extereme end of the shaft 23, adjacent to the pinion 26, is a short section 30, of smaller diameter than the remainder of the shaft 23, that is adapted to ride in a groove 31 in the rack-mounting plate 29 and to enter a plurality of holes 32 located at the ends of the groove 31. To rcvent the rack 26 and the pinion 27 from coming disengaged, and, moreover, to ensure that the tenuous end 30 of the shaft 23 shall be held in the holes 32 when it has once entered them, a double end spring catch 33 is rigidly mounted on one of the bearings 22, and coacts with a plurality of notches 34 to lock the shaft 23 against horizontal shifting when the latter are slid directly under either of its ends by the longitudinal motion of the shaft 23.

A wide horizontal slot 35 is substantially centrally located in the gate-supporting plate 1. The slot 35 has a plurality of parallel tracks 36 milled in its vertical boundaries to slidably support the rack-mounting plate 29. A short horizontal slot 37 is cut in the aperture plate 6 in order that the motion of the rack support 29 shall not be obstructed.

by the plate.

A shoe-carrying-plate 38 having a curved section 39 at the top, is mounted on the flange of a ribbed block 41 that is of.;L section along the center and of rectangular section at the ends and is fastened, by a plurality of screws 42, to the rack mount.

In view of the fact that it is essential that the shoe plate 38 and its mountin be movable without effort, one side of t e stem of the block 41 is given a smooth machined finish and the block is mounted in such manner that this surface slides in engagement with the machined surfaces of a plurality. of bosses 43 of the supportingplate 1.

The shoe-plate 38 is equipped with a rec tangular opening 44 that corresponds to the aperture 7 and to a plurality of rectangular slots 45 symmetricallylocated relative to the opening 44. A plurality of shoe-runner units 46 are loosely mounted in the slots 45 to be resilientlyurged in a direction normal to the plates 6 and 38, and hence, normal to the film 10 positioned therebetween, by a multiple end spring 47 rigidly mounted on a'block 48 that is integral with the plate 38.

In usin amotion picture machines, it happens, at times, that the take-up reel does not function and, in order to minimize the fire risk, steps are ordinarily taken to revent the film from. being projected into t e path of the light beam between the shoe plate and the objective.

In this connection, for the present embodiment of our invention, a flanged tube 49 is provided that is rigidly mounted on the shoe plate 38 to coact with a cylindrical sheet 50 of U-section pivotally supported on one end of an angle bracket 51 that isfastened to the main plate of the machine. The sheet 50 is adapted to be raised to a position wherein it does not obstruct the passage of the shoe- .carrying bracket 29 and its appurtenances,

and it is, moreover, held in its raised position b the action of a spring catch 53 on a note ed plate 54 that is rigidly fastened to the sheet 50. When in its lower position, the sheet 50 forms an enclosure with the main plate of the machine within which are, respectively, the ends 0 the tube 49 carried by t e shoe plate 38 and the end of the objective mount (not shown) thus, the ossibilit of the projection of the film strip into the light beam is entirely eliminated.

Although we have she and described certain specific embodimen of our invention, we are fully aware that many modifiea tions 'thereof are possible. A possible modification of our invention,for example, is the substitution of friction means, for the rack and pinion shown in the present embodiment,

1 pen ed claims. I

as a moving mechanism for the shoe-plate.

'Our invention, therefore, is not to be re strictediexcept insofar as is ntated by the donut and by the spirit of the ap- We cl "m as our invention i I 1. Film-tensioning apparatus comprising move said shoe plate relative to said aperture plate, andmeans for locking said shoe plate 1n one of a plurality of positions.

2. In film-tensionin apparatus, means for moving the aperture p ate relative to the shoe plate 'comprisin a shaft slidably mounted on said aperture p ate, a knob mounted on one terminal of said shaft and dentate means mounted near the other terminal of said shaft, in combination with a support for said shoe plate having rigidly mounted thereon dentate means and havin milled therein indentations that coact with means on said.

shaft to lock said aperture-plate in a plurality of positions.

3. In film-tensioning apparatus, a plurality of plates, means for moving one of said 1 plates relative to another comprising a shaft slidably mounted on one of said plates, a knob mounted on one terminal of said shaft, and ipping means mounted near the other terminal of said shaft, in combination with a support for said remaining plate having mounted thereon gripping meansjand having milled therein indentations that coact with means on said shaft to lock said movableplate in a plurality of positions.

4. A clamping apparatus comprising a casting of T- sections, a track milled in the flange of said T section comprising the female of a dovetail, a plate, COIIIPII the male of said dovetail, having mounted t ereon a clamping member, dentateameans mounted on the stem of said T section coacting with dentate means mounted on the male of said dovetail to move said clamping member relative to said stem of said T section,

.and means on said male of'said dovetail oo- 

